What’s the difference between types of heating fuels?

It may seem strange to us lifelong New Englanders who’ve spent decades of winters checking the gauges on our oil tanks, but did you know that most of the U.S. does not use heating oil to heat their homes? Curious, but true.

While about 5.7 million households in the United States use heating oil as their main space-heating fuel, according to the U.S. Energy Information Administration, types of household heating fuels vary tremendously across the country.

Not surprisingly, the Northeast uses the greatest amount of heating oil— about 20% of the area’s households use it as their main space-heating fuel (accounting for about 80% of the total U.S. households that use heating oil for space heating.1 ) Meanwhile, households in the West use the least, with only 3% of total heating fuel consumption coming from heating oil.

Want more? Perfect, because we love to geek out on this stuff. Again, according to the U.S. Energy Information Administration, the Northeast accounts for 85% of heating oil sales, the South has 6%, the Midwest 5%, and the West only 3%. The top five residential heating oil consuming states in 2017 – in descending order – were New York, Pennsylvania, Massachusetts, Connecticut, and Maine. Raise your hand if you’re shocked.

Right, didn’t think so.

Heating oil is so prevalent in the Northeast that many people who grew up here are not aware that people living in other parts of the country use other types of fuel, such as…

Other types of heating fuels

Nationwide, 50% of homes heat with natural gas. The majority of homes in the West and Midwest use natural gas to heat their homes, whereas electricity is the most widely used form of heating for the South. And, while not the most common, propane is another fuel used to heat homes in the U.S.

So, how do each of these heating fuels differ?

What is natural gas?

Like crude oil, natural gas was formed over millions of years. Its beginnings lie with the algae and plants that lived and died in large and shallow seas. After they died, they sank to the bottom of the seafloor where they mixed with other sediment. Year upon year the material built up as more algae and plants died and mixed with more sediment. After millions of years, pressure from all that weight and temperature built up until the plant matter was transformed into fossil fuels including natural gas.

Natural gas is made up of different compounds, the largest of which is methane. It is found in a variety of areas in both land and sea—in large cracks and spaces between layers of rock (conventional natural gas); in tiny spaces with some shale, sandstone, and other types of sedimentary rock (unconventional natural gas); in deposits with crude oil (associated natural gas); and in coal deposits (coalbed methane).

Like crude oil, natural gas has to be processed in order to be useful. Once it is extracted from the earth, it is sent to a processing plant where water vapor and nonhydrogen carbons are removed and what’s known as NGL (natural gas liquids) are extracted and sold separately.

Natural gas is colorless, odorless, and tasteless. As a safety measure, a substance known as mercaptan is added to natural gas to give it an odor similar to rotten eggs. Gross, right? It’s done as a safety precaution, so that in the event of a natural gas leak, the odor would be detectable. 

What about propane?

Also called LPG for Liquified Petroleum Gas, propane is another type of fossil fuel that can be used to heat a home. It is produced through natural gas processing and petroleum refining during which it is extracted, liquified under pressure, and stored in pressurized containers (just like the tanks you get at the hardware store to run your gas grill). Propane turns back into a gaseous vapor when used.

Like natural gas, propane is odorless, so an odorant is added to make it detectable in the case of leak.

How gas and propane furnaces work

Furnaces powered by gas or propane work much the same way. As with all types of heating sources, the heating cycle begins when the thermostat signals that the air temperature has cooled below the desired level.

Gas furnaces contain a combustion chamber in which air and gas mix and are ignited by an ignition source. Older gas furnaces use a pilot light to ignite the furnace, while more modern gas furnaces use what is known as a ‘glow stick,’ made up of silicon nitride. Once the thermostat signals the ignition source, the gas and air in the combustion chamber are lighted and begin to heat.

A heat exchanger is located above the combustion chamber. The exchanger absorbs as much heat as possible from the combustion chamber and heats the air inside it. When the air reaches a certain temperature, an electric motor kicks in and turns on a fan that moves the warm air into the home’s heating ducts and out into the rooms.

Gas- or propane-powered boilers, work similarly to furnaces, but instead of warming air, they warm water. The heat exchanger is connected to a pipe carrying cold water and takes the heat energy from the gas or propane and uses it to warm the water to around 140 degrees F. The heated water is then sent out to move through either radiators or base boards thereby transmitting the heat to your house.

Electricity for heating

Though expensive, electricity is another heating source used in the U.S. The idea of using electricity for heating began in 1831, when scientist Michael Faraday discovered that when a magnet is moved inside a coil of wire, electric current flows through the wire. With that discovery, the idea of an electricity generator was born.

How do electric heaters work?

An electric furnace is similar to a gas-powered furnace—it simply makes heat with electric heating elements instead of gas burners.

It’s kind of like a big hair dryer. It takes in cold air through a cold-air return, heats the cold air by running it through electric heating elements, and blows the now-heated air out to the house through heating ducts.

The advent of heat pumps

While electric furnaces are expensive to use, heat pumps are less expensive and offer an alternative to furnaces and air conditions. During the heating season, heat pumps use electricity to move heat from the outdoors into your home. You read that right. Because even cold air has some heat in it (think how much warmer 35 degrees feels than 20 degrees), heat pumps can extract it and blow it into your house.

How do heating oil furnaces differ?

Home heating oil heating systems use one of three ways to heat a home: warm air through vents, hot water through baseboards, or steam through radiators.

Like the other heating systems, the thermostat begins the heating cycle when the air temperature drops below the desired temperature. The thermostat signals the burner to turn on and heating oil travels from the storage tank to the burner. A pump mixes the oil with air and injects the fine mist oil mixture into the burner where it is lit in the – you guessed it – combustion chamber.

Delivery of the heat depends on the system used. In a hot water system, water is heated and circulated through radiators or baseboards. In a steam system, water is heated until it becomes steam, which then rises through pipes to radiators. And with a warm air system, air (instead of water) is heated and a blower sends the heated air through heating ducts to heating vents.

What your most familiar with probably depends on where you live. If you’re new to New England and heating your home with heating oil, we’ve got you covered. Our Heating Oil 101 will get you started.

1U.S. Energy Information Administration, Short-Term Energy Outlook, Table WFO1, January 2019.

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